Explanation:
Do stars appear dimmer when nearer the horizon?
Yes -- atmospheric air absorbs and reradiates light, so that the greater the
airmass through which
one peers, the fainter an object will appear.
Pictured above in a multi-frame image, stars, the planet
Jupiter, and even the Moon show the
horizon-dimming effects of Earth's nearly-transparent atmosphere.
The image was taken in the evening about three weeks ago over
Hong Kong,
China.
The brightest streak near the center is the
setting Moon,
while intermittent thin clouds sometimes dispersed moonlight into a
larger halo.
Jupiter sets just to the Moon's right.
The dim steaks cutting across the image horizontally were caused by
passing airplanes.
The bright strange multi-pronged streak over the house is a helicopter taking off.
An astute observer will also notice faint rays emanating from near the horizon.
Their cause is unknown, but may be
crepuscular rays caused by the Sun shining through gaps in thick clouds.